Simplified Network Based Modeling of Cold Plate in a CFD Environment

Author(s):  
Debabrata Pal ◽  
Mark Severson

Thermal management of high power electronics for aerospace applications frequently utilizes liquid or air-cooled cold plates with embedded fin cores. These commonly used cold plates use fin assemblies with small flow passages and large area enhancements to achieve high levels of heat transfer performance. The design of this type of cold plate is well documented in the literature, with the most common methodology utilizing “f” and “j” test data as a function of Reynolds Number. This paper presents a technique termed “network modeling” that simplifies the modeling of cold plate features within a CFD model. This technique greatly reduces model size and CPU time needed for solutions. In addition, it is inherently accurate because it allows test data to be incorporated into the model. Simplification of the performance of coldplate features within a system level CFD thermal model is a great advantage, as modeling these small coldplate features is a tedious task and often unnecessary. The methodology presented uses a convective resistance network with mass flow links and convective links to describe the overall thermal behavior of the coldplate. This simplified network model can be used within a detailed thermal model of the electronics assembly to provide an accurate simplification of the coldplate performance for temperature and heat flow prediction. Since the network technique simplifies the flow boundary conditions, the detailed thermal model can contain as much internal details of an electronics assembly as desired, while still keeping the overall model size manageable and CPU times minimal. This network-based method of modeling coldplate should be very accurate because it is based upon established test data of “f” and “j” as the basis of the model. This network method has significant advantages over the other methods of heat exchanger simplification such as coarse mesh, effective thermal conductivity, source-sink, etc. This paper describes the creation of such a network, integration in an ICEPAK thermal model, discussion of the advantages, and results.

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Peng Wang ◽  
Patrick McCluskey ◽  
Avram Bar-Cohen

Recent trends including rapid increases in the power ratings and continued miniaturization of semiconductor devices have pushed the heat dissipation of power electronics well beyond the range of conventional thermal management solutions, making control of device temperature a critical issue in the thermal packaging of power electronics. Although evaporative cooling is capable of removing very high heat fluxes, two-phase cold plates have received little attention for cooling power electronics modules. In this work, device-level analytical modeling and system-level thermal simulation are used to examine and compare single-phase and two-phase cold plates for a specified inverter module, consisting of 12 pairs of silicon insulated gate bipolar transistor (IGBT) devices and diodes. For the conditions studied, an R134a-cooled, two-phase cold plate is found to substantially reduce the maximum IGBT temperature and spatial temperature variation, as well as reduce the pumping power and flow rate, in comparison to a conventional single-phase water-cooled cold plate. These results suggest that two-phase cold plates can be used to substantially improve the performance, reliability, and conversion efficiency of power electronics systems.


Author(s):  
Levi A. Campbell ◽  
Michael J. Ellsworth ◽  
Arvind K. Sinha

IBM returned to indirect (cold plate) water cooling in 2008 with the introduction of the Power 575 Supercomputing Node [1]. The node, packaged in a super-dense 2U (88.9 mm) form factor, contains 16 dual core processor modules. An assembly of 16 cold plates was developed to cool the processors. The assembly consists of the cold plates (one cold plate for each processor module), copper tubing that connects 4 groups of 4 cold plates in series, copper tubing that connects each grouping of 4 cold plates, or quadrant, to a common set of supply and return headers, and two flexible EPDM hoses that connect the headers to system level manifolds in the rack housing the nodes (a rack can contain up to 14 nodes). Non-spill poppeted quick connects are used to connect the cold plate assembly to the system level manifolds. In addition to a detailed description of the cold plate assembly, an overview will be given of the analysis and design that went into its development. Conjugate computational fluid dynamics (CFD) modeling was done on the cold plate and processor module combination. CFD modeling was done on the headers to verify proper flow balancing. Finally, mechanical finite element analyses were performed to determine the cold plate tube routing necessary to minimize reactionary forces the tubes placed on the cold plates under land grid array loading of the module to the board.


Author(s):  
Yi. Feng ◽  
Y. Wang ◽  
C. Y. Huang

The increasing power consumption of microelectronic systems and the dense layout of semiconductor components leave very limited design spaces with tight constraints for the thermal solution. Conventional thermal management approaches, such as extrusion, fold-fin, and heat pipe heat sinks, are somehow reaching their performance limits, due to the geometry constraints. Currently, more studies have been carried out on the liquid cooling technologies, as the flexible tubing connection of liquid cooling system makes both the accommodation in constrained design space and the simultaneous cooling of multi heating sources feasible. To significantly improve the thermal performance of a liquid cooling system, heat exchangers with more liquid-side heat transfer area with acceptable flow pressure drop are expected. This paper focuses on the performance of seven designs of source heat exchanger (cold plate). The presented cold plates are all made in pure copper material using wire cutting, soldering, brazing, or sintering process. Enhanced heat transfer surfaces such as micro channel and cooper mesh are investigated. Detailed experiments have been conducted to understand the performance of these seven cooper cold plates. The same radiators, fan, and water pump were connected with each cooper cold plate to investigate the overall thermal performance of liquid cooling system. Water temperature readings at the inlets and outlets of radiators, pump, and colder plate have been taken to interpret the thermal resistance distribution along the cooling loop.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yanji Liu ◽  
Guichen Zhang ◽  
Chidong Che

To solve the localization failure problem of terrain-aided navigation (TAN) system of the autonomous underwater vehicle (AUV) caused by large area of underwater flat terrain in the Arctic, a navigation system with relocation part is constructed to enhance the robustness of localization. The system uses particle filter to estimate the AUV’s position and reduce the nonlinear noise disturbance, and the prior motion information is added to avoid the mismatching caused by the similar altitude of low-resolution map. Based on the estimate data and the measured altitude data, the normalized innovation square (NIS) is used to evaluate the differentiation of terrain sequence, and the differentiation is used as a judgment of whether the AUV is in the switch location. A simulation experiment is carried out on the 500 m resolution underwater map of the Arctic. The results show that adding the prior motion information can restrain the divergence of the estimator; NIS can accurately reflect the sharp change of terrain sequence. After the relocation process, the AUV can still maintain the positioning accuracy within 2 km after running 50 km in the area including flat and rough terrain. This research solves the problem of localization errors in the Arctic flat terrain in the system level and provides a solution for the application of underwater navigation in the Arctic.


2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Bharath Ramakrishnan ◽  
Yaser Hadad ◽  
Sami Alkharabsheh ◽  
Paul R. Chiarot ◽  
Bahgat Sammakia

Data center energy usage keeps growing every year and will continue to increase with rising demand for ecommerce, scientific research, social networking, and use of streaming video services. The miniaturization of microelectronic devices and an increasing demand for clock speed result in high heat flux systems. By adopting direct liquid cooling, the high heat flux and high power demands can be met, while the reliability of the electronic devices is greatly improved. Cold plates which are mounted directly on to the chips facilitate a lower thermal resistance path originating from the chip to the incoming coolant. An attempt was made in the current study to characterize a commercially available cold plate which uses warm water in carrying the heat away from the chip. A mock package mimicking a processor chip with an effective heat transfer area of 6.45 cm2 was developed for this study using a copper block heater arrangement. The thermo-hydraulic performance of the cold plates was investigated by conducting experiments at varying chip power, coolant flow rates, and coolant temperature. The pressure drop (ΔP) and the temperature rise (ΔT) across the cold plates were measured, and the results were presented as flow resistance and thermal resistance curves. A maximum heat flux of 31 W/cm2 was dissipated at a flow rate of 13 cm3/s. A resistance network model was used to calculate an effective heat transfer coefficient by revealing different elements contributing to the total resistance. The study extended to different coolant temperatures ranging from 25 °C to 45 °C addresses the effect of coolant viscosity on the overall performance of the cold plate, and the results were presented as coefficient of performance (COP) curves. A numerical model developed using 6SigmaET was validated against the experimental findings for the flow and thermal performance with minimal percentage difference.


2020 ◽  
Vol 110 (7-8) ◽  
pp. 2105-2117
Author(s):  
Omar Baho ◽  
Gilles Ausias ◽  
Yves Grohens ◽  
Julien Férec

Abstract Laser-assisted automated fiber placement (AFP) is highly suitable for an efficient production of thermoplastic-matrix composite parts, especially for aeronautic/aerospace applications. Heat input by laser heating provides many advantages such as better temperature controls and uniform heating projections. However, this laser beam distribution can be affected by the AFP head system, mainly at the roller level. In this paper, a new optico-thermal model is established to evaluate the laser energy quantity absorbed by a poly(ether ether ketone) reinforced with carbon fibers (APC-2). During the simulation process, the illuminated radiative material properties are characterized and evaluated in terms of the roller deformation, the tilt of the robot head, and the reflection phenomenon between the substrate and the incoming tape. After computing the radiative source term using a ray-tracing method, these data are used to predict the temperature distribution on both heated surfaces of the composite during the process. The results show that both the roller deformation and the tilt of head make it possible to focus the laser beam on a small area, which considerably affects the quality of the finished part. These findings demonstrate that this optico-thermal model can be used to predict numerically the insufficient heating area and thermoplastic composites heating law.


2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Cheng-Wei Tien ◽  
Kun-Huang Yu ◽  
Wen-Junn Sheu ◽  
Chi-Chuan Wang

This study examines the refrigerant distribution of a dual cold-plate system subject to the influence of heating load, using a R-134a based vapor compression system with a nominal capacity ranging from 50 W to 250 W. The cold plate is of identical configuration. Initially, test is performed under an equal heating load for each cold plate (70 W), which then gives rise to a uniform distribution and equal outlet superheat condition. For an unequal heating load, it is found that the distribution of mass flowrate subject to the influence of heating load is strongly related to the outlet states of the two cold plates. For the condition where one of the cold plates is in superheated state while the other is in saturated state, the mass flowrate for the fixed heating load is lower than that of smaller heating load, and the difference increases when the heating load gets smaller due to the influence of accelerational pressure drop. A maximum of 17% difference is seen at a loading ratio of 0.571 (40 W/70 W). For the condition where both outlet states of the cold plate are at superheated states, the mass flowrate for the fixed heating load is marginally higher than that of the smaller heating load, and the difference is insensitive to the increase in heating load. For this situation, the effect of accelerational pressure is negligible, and it is mainly attributed to two-phase/single-phase distribution pertaining to the effect of heating load.


1997 ◽  
Vol 07 (02) ◽  
pp. 115-127 ◽  
Author(s):  
SUE TENG ◽  
TIEN-YU TOM LEE ◽  
MALI MAHALINGAM ◽  
BENNETT JOINER
Keyword(s):  

Author(s):  
Sarng Woo Karng ◽  
Kyudae Hwang ◽  
Jongmin Moon ◽  
Seo Young Kim

Thermal performance for mini water-cooled cold plates covered with non-metallic polycarbonate (PC) is experimentally measured in this study. The mini cold plates are designed to reduce the overall weight of the cooling device for effective heat dissipation from a humanoid robot. The water-cooled cold plate has a 10×10 mm2 of base plate which is made of copper or aluminum. Two different types of enhanced surfaces are considered in the present study: copper pin-finned surface of 0.5×0.5 mm2 area and 1.5 mm high with 0.5 mm fin spacing and aluminum foam-finned surface of 92% porosity and 40 PPI (pores per inch). Heat transfer rates are measured according to the input power and the flow rate of cooling water. The surface temperature of the base plate and the cooling water temperatures at inlet and outlet of each cold plate are measured. From the results, it is found that the copper pin-finned cold plate shows better performance than the aluminum foam-finned cold plate in terms of thermal resistance and pressure drop.


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